Yes, that figure in the image is an astronaut and he is intercepting a satellite in the middle of space. The photograph was taken on November 14th, 1984, while floating 210 miles over The Bahama Islands. His name is Dale A. Gardner and in the image he has just left Discovery shuttle, floated about 50 meters through the empty space and then captured the Westar 6.

During this strange rendezvous, Gardner is wearing the Manned Maneuvering Unit (MMU) and using a large tool called the Apogee kick motor Captured Device (ACD). He uses it to attach it to “the nozzle of the spent Westar engine and stabilize the satellite to capture it for return to Earth”.

According to Wikipedia, STS-51-A mission was unique in that it marked the first time the shuttle had deployed two communications satellites, and retrieved from orbit two other communications satellites. Palapa B-2 and Westar 6 had been deployed during the STS-41-B mission earlier in the year, and had been placed into improper orbits because their kick motors malfunctioned.

After this mission, NASA decided to discontinue untethered spacewalks. The satellite recoveries on this mission were the last untethered spacewalks until 1994 and the last use of the Manned Maneuvering Unit. All subsequent spacewalks by NASA and the Soviets/Russians have had the astronauts tethered to the craft by some means.

In this video, Gardner and Allen explain the details on the mission. Gardner says he had a lot of fun during his incredible spacewalk. Please watch his flight:

After retrieving the two satellites, Dale Gardner and Joseph P. Allen took their famous picture showing the message "For sale". The Westar 6 and Palapa B2 recoveries were funded by the insurance companies that insured the launch of those two satellites. Both were brought back to earth and refurbished. Westar 6 was later resold to China, and relaunched on April 7, 1990, as AsiaSat 1.

Astronaut Dale A. Gardner, having just completed the major portion of his second extravehicular activity (EVA) period in three days, holds up a "For Sale" sign refering to the two satellites, Palapa B-2 and Westar 6 that they retrieved from orbit after their Payload Assist Modules (PAM) failed to fire.